Horizontal lines are parallel to the horizon or parallel to level ground. They have a slope of zero and are parallel to the x-axis on a graph. Vertical lines are perpendicular to the horizon, parallel to the y-axis on a graph and have undefined slope.
Know MoreThe term "horizontal" derives from the Latin "horizontem" which means "flat." The term "vertical" derives from the Latin "vertex," which means "highest point."
The slope of a line refers to the change in the rise, or y-value, divided by the run, or the change in x-value. Because a horizontal line does not change in y-value with changes in x-value, its slope may be calculated as zero divided by any number. This results in a slope of zero. For vertical lines, the slope equation leads to a division by zero, which is undefined.
Learn more about ShapesCircles have an infinite number of lines of symmetry. Any line that bisects a circle through its center is a line of symmetry. Circles are the only Euclidean shape with this property.
Full Answer >A rhombus has only two lines of symmetry. A rhombus is a four-sided, two-dimensional shape, also called a diamond, that falls under the category of quadrilaterals. Its sides are the same length, but angles are not 90 degrees.
Full Answer >Contour lines do not ever cross one another because each line represents a different elevation on a topographic map. However, contour lines may merge in the case of a vertical cliff.
Full Answer >Some shapes that have no lines of symmetry include the scalene triangle and trapezium. A trapezium is a four-sided flat shape with straight sides, none of which are parallel. Outside of the United States, the trapezium is called the general irregular quadrilateral.
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